One World, One Exchange

Updated May 4, 2000 12:01 a.m. ET

I f the only closed economy is the world economy, there is no reason why it shouldn't be served by one single gridwork that connects world investors to world companies. So the announced merger of the London Stock Exchange with the Deutsche Boerse, with plans for a later linkup with Nasdaq and the Madrid and Milan bourses, should be cautiously welcomed. The efficiencies of such an integrated global exchange might reach even those who neither lend nor borrow.